Most auto-loading firearms include a frame or receiver, a barrel mounted to the frame or receiver, and a slide or bolt movably mounted to the frame or receiver for reciprocating motion to lock or open a chamber formed in the barrel. During discharge of such a firearm, the slide or bolt is locked against the chamber. Following discharge of the firearm, the slide or bolt retracts to extract the discharged or spent round from the chamber.
One type of extractor mechanism includes a substantially flat steel member that is mounted to the slide or bolt. A hook or claw is positioned on the forward end of the member to engage the rim of the spent round while the round is locked within the chamber of the firearm. When engaged, the hook positions the rim of the casing in a space between the hook and a breech face of the slide or bolt. Upon operation of the firearm, the firing pin or striker projects from the breech face to detonate the primer of the round, thus igniting propellant to discharge a bullet down the barrel.
Upon discharge of the round or cartridge (or by manually drawing the slide or bolt from its forward (battery) position to its rearward (retired) position), the extractor hook grips the rim of the round to pull the round from the chamber. By interaction with an ejector mechanism housed or formed in the bolt, frame, or receiver, the extractor hook or claw holds the round in position to be hit by the ejector. The ejector holds the round in a stationary position as the slide continues rearward, the round rotates about the extractor and then launches out through the ejection port formed in the frame, slide, or receiver, thereby clearing the round from the firearm to permit loading a next round.
Typically, the next round is supported by a magazine at a feed opening disposed rearward from and below the chamber. As the bolt or slide of the firearm moves forward from its retired position, the rim of the round is caught between the breech face and the extractor claw, and the round is swept from the magazine feed opening into the chamber. As will be readily appreciated, however, the smaller the gap between the extractor claw, the greater the chance that the extractor could hinder the chambering of the round.
Thus, a dimension from the breech face to the extractor hook is important to the operation of the gun. At the beginning of the loading operation, it is advantageous to have this dimension as large as possible so that the rim of the round can easily pass between the breech face and the extractor claw and into position within the chamber. Given the geometry of pistol cartridges, however, this dimension (breech face to extractor hook) is typically limited.
Accordingly, a need exists for an extractor hook that can provide optimal clearances from a breech face during loading, firing, and ejection of a round.